Sulfonamides are one of the oldest classes of antibacterial drugs used to treat infections. They work by inhibiting the bacterial synthesis of folic acid, making them bacteriostatic. While their use has decreased with newer antibiotics, they remain an alternative for those allergic to penicillin and are used to treat urinary tract infections, ear infections, and other bacterial infections. Common side effects include rashes, nausea, and hematologic issues like anemia. Nursing care involves monitoring for side effects, ensuring adequate hydration when taking the drug, and patient education.

1. SULFONAMIDES
Dr.Gurumeet C Wadhawa ,Assistant Professor, Department of Chemistry.
Rayat Shikshan sansthas Veer Wajekar ASC College,Phunde,Uran

2. Description
 One of the oldest antibacterial agents used to
combat infection
 Used for coccal infection in 1935
 They are bacteriostatic because it inhibits
bacterial synthesis of folic acid
 Clinical usefulness has decreased because of
the effectiveness of other antibiotics and
penicillin

3.  Alternative drug for clients allergic to
penicillin
 Not effective against viruses and fungi

4. Mode of action
 Inhibit bacterial growth without affecting
normal cells
 Sulfonamides therefore are reversible
inhibitors of folic acid synthesis and
bacteriostatic not bacteriocidal.

5. Indication & Contraindication
 To treat urinary tract (E.coli) and ear
infection
 Newborn eye prophylaxis
 Meningococcal meningitis
 Against Chlamydia and Toxoplasma
gondii

6. Pharmacokinetics
 Well absorbed in the GI tract
 Well distributed to body tissues and brain
 Liver metabolizes and kidney excrete it

7. Pharmacodynamics
 For oral administration
 Highly protein bound
 2 categories of sulfonamide according to their
duration of action:
1. Short acting sulfonamides (Rapid absorption
and excretion rate)
2. Intermediate acting sulfonamides (Moderate
to slow absorption and slow excretion rate)

8. Short acting sulfonamides
DRUG Protein
binding (%)
Half-life
(hour)
Solubility
in urine
Sulfadiazine
(Microsulfon)
20-60 17 +1
Sulfamethizole
(Thiosulfil)
90 2.5 +3
Sulfisoxazole
(Gantrisin)
90 5-7.5 +3

9. Short acting sulfonamides
DRUG Uses Considerations
Sulfadiazine
(Microsulfon)
Systemic infection -Increase oral fluid
intake (2000ml/day)
-pregnancy category: C
Sulfamethizole
(Thiosulfil)
UTI
Highly soluble
-Increase oral fluid
intake (2000ml/day)
-pregnancy category: C
Sulfisoxazole
(Gantrisin)
UTI
Prophylaxis of otitis
media
-Ordered with one time
initial loading dose
-Fluid intake greater
than or equal to
2000ml/day
-pregnancy category: C

10. Intermediate acting sulfonamides
DRUG Protein
binding
(%)
Half-life
(hour)
Solubility
in urine
Sulfamethoxazole
(Gantanol)
85-90 11 +1
Sulfasalazine
(Azulfidine)
99 5-10 +1
Trimethoprim
sulfamethoxazole
50-65 8-12 +1-2

11. Intermediate acting sulfonamides
DRUG Uses Considerations
Sulfamethoxazole
(Gantanol)
-UTI, otitis media and
meningococcal
-Meningitis prophylaxis
-Fluid intake atleast
2000ml/day
-pregnancy category: C
Sulfasalazine
(Azulfidine)
Ulcerative colitis,
Crohn’s Disease,
rheumatoid arthritis
Take after eating
Trimethoprim
sulfamethoxazole: co-
trimoxazole (Bactrim,
Septra)
Urinary tract anti-
infectives, effective
against gram-negative
bacteria
-Drug ratio 1:5 (1 part
trimethoprim, 5 part
sulfamethoxazole)
-pregnancy category: C

12. Side effects & Adverse effects
 Allergic response: skin rash, itching
 Hemolytic anemia, aplastic anemia, low WBC
and platelet counts
 GI disturbances: anorexia, nausea and
vomiting, diarrhea
 Crystalluria, hematuria, photosensitivity

13. Side effects & Adverse effects
 Cotrimoxazole
- anorexia, nausea, vomiting, diarrhea,
rashes, stomatitis, fatigue, depression, head
ache, vertigo, photosensitivity
- life-threatening: leukopenia,
thrombocytopenia, increase bone marrow
depression, hemolytic anemia, aplastic anemia,
agranulocytosis, Stevens-Johnson syndrome
and renal failure

15. Nursing Process
 Assessment
- Assess client’s renal function by checking urinary output
(greater than 600ml/day), BUN (8-25mg/dL), Serum
creatinine (0.5-1.5)
- Obtain medical history: TMP-SMZ. Contraindicated for
client with severe renal and liver disease. Hypersensitivity
to sulfonamides
- Drug history of drugs client usually takes, oral antidiabetic
drugs (sulfonylureas) + sulfonamides = increase
hypoglycemic effects. Warfarin + sulfonamides = increase
anticoagulant effect
- Assess CBC

16.  Diagnosis: Risk for infection, risk for impaired
integrity, impaired urinary elimination
 Planning: client’s infection will be controlled
 Nursing interventions:
1. Administer with full glass of water.
2. Record client’s I&O
3. Monitor VS
4. Observe for hematologic reactions
5. Observe for signs and symptoms of super infection
6. Client teaching:
a. Instruct client to drink several glass of water
b. Advise pregnant women to avoid sulfonamides
during the last 3 months of pregnancy

17. c. Inform client not to take antacids
d. Warn client who has an allergy
e. Take 1 hour before or 2 hours after meal with full
glass of water
f. Report bruising or bleeding
g. CBC monitoring
h. Avoid direct sunlight, use sun block and
protective clothing